‘Consequences and cost for town’s problematic Victorian drainage system are not to be ignored’

Developers behind a planned 113-home retirement community at Knowle have been accused of putting profit before people by objectors who have slammed ‘minimalist flood prevention measures’.

Residents already concerned about the proposed size and scale of the development say new documents outlining ‘limited’ water retention on the site have done little to alleviate fears that it will exacerbate the risk of flash-flooding in Sidmouth.

Developer PegasusLife insists the drainage design proposed in its planning application actually reduces peak discharge rates by 50 per cent and includes provision for storing water in attenuation tanks at Knowle, thereby protecting the town’s lower properties.

In a letter submitted to East Devon District Council’s (EDDC) planning department, the company details limitations of the site that mean original plans for diverting excess water into ‘soakaways’ are ‘not technically feasible’.

It concludes that accommodating a larger volume of water storage is ‘not viable in terms of cost for the project’.

Referring to the letter, Ed Dolphin, of Knowle Drive, said: “Bearing in mind the huge profit the company stands to make by trying to cram more than 100 apartments onto the site, this does not wash.”

He said that the risk of flash-flooding is only likely to increase in coming years with ever-changing weather patterns, adding that the ‘overdevelopment’ of Knowle is a serious concern to householders.

Piers Brandling-Harris, also of Knowle Drive, said: “The concern is that by raising ground levels in certain areas, increasing hard-standing surfaces and generally putting in - what appears to us to be - minimalist mitigation measures, the legacy for us could be very damaging.”

Sidmouth’s surface water management plan predicts £12million worth of damage to the town centre over a 50-year period if such flooding is not reduced. Campaigners argue the developer should be doing more to mitigate this risk.

In a written objection on behalf of the Futures Forum of the Vision Group for Sidmouth, Jeremy Woodward said: “There must be serious concerns about the likely impact on properties at the southern edge of the development that will be at the bottom of what is effectively a large concrete ski-slope.”

Jacqueline Green, of Cotlands, said: “The consequences and cost for Sidmouth town’s already-problematic Victorian drainage system are not to be ignored.”

A spokeswoman for PegasusLife said: “The current site directly discharges into the South West Water (SWW) sewer network without any attenuation. The drainage design proposed has adequate attenuation to reduce the peak discharge rates by 50 per cent - therefore the proposed development reduces the risk of flooding downstream.”

She added that the proposed drainage system meets the Government’s sustainable drainage system requirements.

Devon County Council objected to initial plans to redevelop Knowle on the grounds of surface water management. It is yet to respond to the renewed proposals.

A DCC spokesman said: “We are working closely with EDDC and the applicant to ensure that the surface water from the proposed redevelopment is managed appropriately. The aim is to achieve as close to the greenfield conditions as possible and, as this is a brownfield site, it is essential that the current level of surface water management is not reduced and, where possible, it’s improved. If soakaways are not a viable solution, then storage attenuation tanks with controlled discharge will need to be provided.”